Electron beam recording materials

ABSTRACT

An electron beam recording material consists of a support, a silver halide photosensitive layer thereon, an opaque layer on the photosensitive layer and a thin metallic layer of 50-1,000 A. thickness, vacuum deposited on the opaque layer and an additional opaque layer on the rear side of the support, with the metallic layer preventing scattering of the electron beam during recording.

United States Patent Sato et al.

[ Sept. 5, 1972 [54] ELECTRON BEAM RECORDING MATERIALS I [72] Inventors: Masantichi Sato; Seiji Matsumoto; Satoru Honjo; Yoshilride Hayakawa, all of 105, Oaza Mizonuma, Asakashi, Saitama, Japan [22] Filed: June 14, 1971 [2]] Appl. No.: 152,842

[30] Foreign Application Priority Data 2,372,170 3/1945 Balger ,2 59/49, 5

2,748,288 5/1956 Saulnier, Jr ..250/65 3,336,596 8/ 1967 Dubbe et al. ..346/135 3,510,348 5/1970 Brooks et a1 ..117/201 3,631,514 12/1971 Lee etal ..346/135 Primary Examiner-William F. Lindquist Attorney-Sughrue, Rothwell, Mion, Zinn and Macpeak [57] ABSTRACT An electron beam recording material consists of a support, a silver halide photosensitive layer thereon, an opaque layer on the photosensitive layer and a thin metallic layer of 50-1,000 A. thickness, vacuum deposited on the opaque layer and an additional opaque layer on the rear side of the support, with the metallic layer preventing scattering of the electron beam during recording.

8 Claims, 2 Drawing Figures PATENTEBSEPYSIQR I 3.689.768

IN'VENT'ORS "MAsAmcm SATO SEIJJ MATSUMOTO SATORU HONJO YOSHIHIDE HAYAKAWA "ATTORNEYS 1 ELECTRON BEAM RECORDING MATERIALS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved electron beam recording material.

2. Description of the Prior Art In electron beam recording, a modulated electron beam is impacted upon an electron beam recording material in vacuo to form a latent image and then the latent image is developed in a proper manner to provide an image.

For instance, an electron beam is impacted upon a silver halide emulsion layer to form a chemical latent image and then the recording material is withdrawn in air and comes into contact with a chemical developing solution to develop the latent image.

In general, the electron used for the electron beam recording has a far larger energy than photons of visible light and ultraviolet rays and thus recording material with less sensitivity may be employed. An electron beam recording material that has hitherto been employed has, generally, low sensitivity to visible light or ultraviolet rays. However, since handling of such recording material under room light causes intense fogging, the recording material must be handled in a dark room or under subdued light. Therefore, the elec- I tron beam recording material has such difficulty of handling that the irradiation of electron beam must be conducted in the dark or under a safe light.

Although the recording by electron beam has such merit that the scanning speed is high and high recording density can be obtained, it has, on the other hand, the demerit that the succeeding beam electron is repulsed by the electrostatic charge due to the beam that has previously reached the recording layer and is deflected thereby. Such an undesirable deflection of electron beam reduces the resolution of the recorded image.

SUMMARY OF THE INVENTION An object of this invention is, therefore, to provide an improved electron beam recording material that can prevent the occurrence of the above-mentioned undesirable deflection of electron beam. Another object of this invention is to provide an improved electron beam recording material that can be handled safely under light room.

BRIEF DESCRIPTION OF THE DRAWINGS Now, the invention will be described by referring to the accompanying drawings, in which:

FIG. 1 is a cross sectional view showing an embodiment of the electron beam recording material of this invention, and

FIG. 2 is a cross sectional view showing other embodiment of the electron beam recording material of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the figures, the electron beam recording material of this invention is composed of a support 13 having thereon a recording layer 12 which is photosensitive and can form a latent image by the impact of an electron beam, an opaque layer 11, and a thin metallic layer 10 formed by vacuum deposition. Also, an opaque layer 14 is formed at the back side of the support 13.

As the materials for the support 13, triacetyl cellu lose, polyvinyl chloride, polyvinylidene chloride, polyethylene terephthalate, polyethylene, polycarbonate, etc., may be employed in this invention.

Any recording layers ordinarily used in this field may be used as the recording layer 12, that is to say, a material which is photosensitive and can form a latent image by the impact of an electron beam may be employed asthe recording layer 12 and as such photosensitive materials there are included: a gelatino silver ha.- lide emulsion and a vacuum-deposited silver halide photosensitive layer.

The opaque layer 11 is formed on the recording layer 12. The tenn opaque of the opaque layer 11 means that the layer is opaque to the light in the photosensitive region of the recording layer 12.

The opaque layer 14 is formed on the back side of the support 13. The opaque layer 14 is also opaque to the light in the photosensitive region of the recording layer 12 as in the case of the opaque layer 11.

The thin metallic layer 10 is formed on the opaque layer 11 by vacuum deposition. The thin metallic film 10 is required to be electrically conductive, preferably have a volume specific resistance less than 10 ohms/cm, and be electron-permeable. Practical examples of the metals used as the thin metallic films 10 are aluminum, zinc, beryllium, chromium, cobalt, copper, germanium, gold, iron, lead, nickel, silver, tin, titanium, and the like. Because too light a thickness of the metallic film 10 reduces the electric conductivity of the metallic layer, while too heavy a thickness thereof reduces the electron permeability, which results in making the practical use of such metallic layer unsuitable, the thickness of the thin metallic layer 10 is ordinarily in a range of from 50 A. to 10,000 A., preferably from A. to 1,000 A.

The opaque layer 11 is required to be opaque to the light in the photosensitive region of the recording layer 12 and, for instance, it is most desirable that the layer 11 be black. However, if the photosensitive region of the recording layer 12 is in a blue region or an ultraviolet region, the recording layer is insensitive to red light and thus the color of the opaque layer 11 is not necessarily black but may be red to yellow. The opaque layer 11 is also required to be electron penetrative. Practically speaking, a mixture of a colored pigment and a polymer or a polymer colored by a dye is used as the material for the opaque layer 11. From the view point that an electron penetrates well and scatters to a small extent, it is more desirable to use a dye than to use a pigment. Practical examples of the pigment used for the purpose include carbon black, graphite, Phthalocyanine Black, Aniline Black, Toluidine Red, Iron Oxide Black, Brilliant Carmine 6B, Hansa Yellow, Benzidine Yellow, Chrome Yellow, and various other lake pigments. Examples of the polymer to be mixed with the pigment are acrylic polymer, polyvinyl acetate, silicon resin, alkyd resin, polystyrene, styrenebutadiene copolymer, vinyl chloride-vinyl acetate copolymer, nitrocellulose, ethylcellulose, polyvinyl alcohol, gelatin glue, casein, egg albumin, and other various oleophilic and hydrophilic polymers.

Also, as the dyes used together with the polymer, there are many hydrophilic dyes and oleophilic dyes. The practical examples of the hydrophilic dyes are various magenta dyes and yellow dyes, such as Acid Red 6 (C. I. 14680), Acid Violet 2 (C. I. 18055), Acid Violet 9 (C. I. 45190), Acid Violet 12 (C. I. 18075), Acid Violet 19 (C. I. 42685), Acid Red 34 (C. I. 17030), Acid Red 80 (C. I. 68215), Acid Yellow 11 (C. I. 18820), Acid Yellow 23 (C. I. 19740), Acid Yellow 34 (C. I. 18890), Direct Yellow 12 (C. I. 24895), Acid Orange 3 (C. I. 10385), Mordant Yellow 1 (C. I. 14025), Mordant Yellow 14 (C. I. 14055), Mordant Violet 19 (C. I. 43551), and Mordant Violet 4 (C. I. 14760).

Some practical examples of the oleophilic dyes are Oil Red (C. I. 12140), Oil Red B (C. I. 26105), Oil Yellow AB (C. I. 11380), Nigrosine Base (C. I. 50415), Oil

. Black BT (C. I. 26150). Further, Solvent Black 18 (an example of the commercially available dyes of this kind is Grasol Fast Black G made by Geigy AG) is also preferable although the color indices and the chemical structures of this dye are not yet clear.

The thickness of the opaque layer 11 is 0.2- microns, preferably 0.2-2 microns. Also, it is necessary that the permeability of the opaque layer 11 be less than percent, preferably less than 1 percent to blue light or ultraviolet rays. If the penetrability of the layer is less than 0.1 percent, the recording material can be handled in light room for a long period of time.

The opaque layer 14 is not necessarily electron permeable since the layer 14 is formed for making the recording layer opaque to light. Therefore, it is possible to contain a large amount of pigment in the opaque layer to reduce sufiiciently the permeability of light. The thickness of the opaque layer is from 1 micron to 10 microns or may be thicker than this. The light permeability of the opaque layer 14 can be readily reduced less than 0.01 percent.

For producing the recording material of this invention, the opaque layer 14 is first formed on the back surface of the support and then the recording layer 12 is formed on the opposite side of the support. Then, the opaque layer 11 is formed on the recording layer and finallythe thin metallic layer 10 is formed on the opaque layer 11. Of course, the recording material may be produced by other manners.

Another advantage of this invention is that a metal having a high vacuum evaporation temperature, such as silver, gold, iron, aluminum, copper, nickel, chromium, etc., can be used as the material for the thin metallic layer. If the opaque layer 11 is absent, the recording layer will be exposed to the light emitted when the metal to be vacuum deposited is heated to a high temperature sufficient to cause vacuum .evaporation, whereby the recording layer will be fogged uniformly. The vacuum deposition of the metal may also be conducted immediately before the electron beam recording by utilizing the common vacuum system for the recording.

Asphalt or pitch may also be utilized as the opaque layers 11 and'14.

Because the feature of this invention is in the point that the recording material can be handled easily in a light room, the transparent optical density of the opaque layer (the layer 11 or 14) is desirably higher than 2 to the light to which the underlying photosensitive layer exhibits the maximum sensitivity.

Though in the embodiment of this invention shown in FIG. 1, the opaque layers are formed only on the recording layer and the back side of the support, the opaque layers may be provided to the sides of the recording layers and the support for preventing the entrance of light from the sides of the recording layer and the support. Also, the recording material of this invention may have the structure shown in FIG. 1, in which both the sides of the recording layer 12 are covered by the opaque layer 1 1.

In the use of the recording material of this invention, a latent image is first formed on the recording layer by the action of an electron beam in vacuo and then after withdrawing the recording material in air, the recording layer is subjected to a developing treatment. Prior to the developing treatment the thin metallic film 10, the opaque layer 11 and the opaque back layer 14 may be dissolved away. Or, these layers may be dissolved away during development. In case of reading out by electron beam, it is more profitable not to remove the thin metallic film 10.

When the thin metallic film 10 is formed from a metal more basic than silver, the opaque layer contributes also as a protective layer for preventing the silver halide in the photosensitive layer from being reduced into silver by the interaction with the metal in I the film 10. When a metal nobler than silver is used, no trouble of reduction of silver halide occurs.

As mentioned before, the use of the dye is more preferable than the use of the pigment in the opaque layer 11 since the scattering of electron beam is less in case of the dye.

It is desirable that the opaque layerat the back side of the support be removed because the image formed can be observed or read by transmitted light at the reproduction of the image. In case of reproducing the image by scanning the image with electron beam, the support may be non-lighttransmissive and for such use an opaque support may be used. Also, the opaque layer itself may be removed or the dye in the opaque layer may be bleached during the treatment.

EXAMPLE 1 One side of a polyethylene terephthalate film having a thickness'of microns, both surfaces of which had been irradiated by ultraviolet rays, was coated with a mixture of nitro cellulose and carbon black having the following composition in a dry thickness of 5 microns;

(by wt.)

Carbon black (mean grain size 0.1;1.) 50 parts Nitrocellulose 20 parts Ethanol parts Butyl acetate 20 parts Black dye, Grasol Fast Black G (made by Geigy AG) Polyvinyl acetate 50 parts 10 parts Methanol 200 parts Then, aluminum was vacuum-deposited on the opaque layer formed above in the thickness of 400 A. under the conditions of 1,000" C. in vacuum evaporation temperature and 5 X lmm Hg in pressure.

By using the recording material prepared above, a latent image was formed by means of an electron beam recording device under the following conditions:

Beam voltage 15 RV Beam current 5p. amp. Beam diameter 5 microns Beam staying time sec. Pressure 10" mm Hg.

The recording material having the latent image thus formed was withdrawn from the recording system in air and subjected to the following treatment.

The recording material was first immersed in methanol for 2 minutes to'dissolve away the black polyvinyl acetate layer and remove at the same time the thin metallic film. Then, the recording material was rinsed with fresh methanol for 10 seconds and then washed with water for about 30 seconds. Thereafter, the recording material was immersed in a developing solution for 90 seconds. The solution was prepared by dissolving the pre-mixed developing composition Papitol (trade name of Fuji Photo Film Co.) in water. After development, it was immersed again in 1 percent aqueous acetic acid solution for 1 minute, and then fixed in a fixing solution prepared by dissolving a premixed fixing composition Fuji Fix (trade name of Fuji Photo Film Co.) in water for 3 minutes. After fixing, therecording material was washed with water for 10 minutes and dried. Finally, the recording material was immersed in butyl acetate for 2 minutes to dissolve away the carbon black-containing back layer, washed with fresh butyl acetate, and then dried to provide a clear image.

When the opaque layer having the same composition as that of the dye-containing layer formed on the silver halide emulsion layer in the above procedure was applied as the back layer in place of the carbon blackcontaining back layer, both opaque layers could be dissolved away in the first dissolution treatment.

EXAMPLE 2 A recording material was produced by the same manner as in Example 1 except the following conditions.

The opaque layer 11 was formed by applying the coating liquid having the following composition in a dry thickness of 1 micron:

Polyvinyl alcohol I 50 parts Dyes: Acid Yellow 34 (C. I. 18890) 2 parts Acid Red 80 (C. I. 68215) 3 parts Solvent: water 150 parts After forming a latent image by processing the recording material thus produced as in Example 1, the recording material was immersed in water for about 2 minutes before development to dissolve away the opaque layers, subjected to the developing treatment and fixing treatment as in Example 1, and dried to provide a clear image. 1

EXAMPLE 3 A recording material was produced by the same manner as in Example 1 except the following conditions.

The opaque layer llwas formed by applying a coat- I ing liquid having the following composition and having incorporated therein a hardening agent in a dry thickness of 1.2 microns:

Gelatin l0 pans Dye: Acid Red 1 (C. 1. 18050) 2 parts Water 200 parts The thin metallic layer was formed by vacuum depositing zinc on the opaque layer 11 in a thickness of 800 A. under the conditions of 300 C. in vacuum evaporation temperature and 2 X 10- mm Hg in pres-- sure.

The opaque back layer 14 was formed by applying the coating liquid having the following-composition in a dry thickness of 3 microns:

Polyvinyl acetate 50 pans Carbon black (mean grain size 0.1 15 parts Methanol 200 parts EXAMPLE 4 A recording material was produced by the same manner as in Example 1 except the following conditions:

The opaque layer 11 was formed by applying the coating liquid having the following composition in a dry thickness of 1.2 microns:

Vinyl acetate-maleic anhydride copolymer 20 pans Dyes: Oil Red B (C. I. 26105) 4 parts Oil Black BT (C. I. 26150) 2 parts Solvents: acetone 200 parts dioxane 50 parts The thin metallic film was formed on the opaque layer 11 by vacuum-depositing thereon aluminum in a thickness of 500 A. under the same conditions as those in Example 1.

The opaque back layer 14 was formed by applying the coating liquid having the same composition as that of the opaque layer 1 1 in a dry thickness of 2 microns.

After forming a latent image as in Example 1, the recording material was developed for 2 minutes by using the developing liquid of the same composition as in Example 1, whereby the opaque layers were dissolved in the developing solution and the metallic film was at the same time stripped off. Then, the recording material was fixed as in Example 1, washed with water, and dried.

EXAMPLE 5 The same procedure as Example 4 was followed except that carbon black having a mean grain size of 0.1 microns was used in place of the dye in the opaque layers 11 and 14. Since carbon black particles were dispersed in the opaque layer 11, the clearness of the image obtained was reduced a little owing to the scattering of electron beam.

EXAMPLE 6 In each of the above-mentioned examples the opaque layers were applied only to the upper surface of the photosensitive layer and the back surface of the support but in such structure the edge portions of the recording material were fogged by the entrance of light through the sides of the support and the photosensitive layer. For overcoming these difficulties, the opaque layer was applied also to the sides of the support and the photosensitive layer in this example, whereby no fog was formed.

EXAMPLE 7 Pitch was used as the opaque layers. That is, in the same procedure as Example 1, both the opaque layers were formed each by applying a solution of pitch for lens polishing in toluene in a dry thickness of 1.5 microns. As aluminum thin film was also formed as in Example 4. After forming a latent image by the same manner as Example 1, the opaque layers were dissolved away by toluene before development, whereby the aluminum film was stripped off at the same time. After washing with acetone and then with water, the recording material was developed and fixed as in Example I, washed with water and dried.

What is claimed is: 1. An electron beam recording material comprising: asupport, a silver halide photosensitive layer formed on the support,

an opaque layer formed on the silver halide photosensitive layer, said opaque layer preventing the penetration of light into the photosensitive region of the photosensitive layer and allowing the penetration of an electron beam,

a thin metallic layer of 50-10,000 A. thickness vacuum deposited on the opaque layer, and

an opaque layer formed on the back side of said support, said opaque layer formed on the back side of the support preventing the penetration of the light into the photosensitive region of the photosensitive layer.

2. The electron beam recording material as set forth in claim 1, wherein said support is a plastic base.

3. The electron beam recording material as set forth in claim 1 wh rein said 0 a ue la er formed on the silver halide p hotosensitiv l ayer is a mixture of a polymer and one material of the group consisting of a pigment and a dye.

4. The electron beam recording material as set forth in claim 1, wherein said opaque layer formed on the back side of the support is a mixture of a polymer and one material of the group consisting of a pigment and a dye.

5. The electron beam recording material as set forth in claim 1, wherein the thickness of the opaque layer on the photosensitive layer is 0.2-5 microns and the thickness of the opaque layer on the back side of the support is l-10 microns.

6. The electron beam recording material as set forth in claim 1, wherein at least one of said opaque layers is made of pitch.

7. The electron beam recording material as set forth in claim 1, wherein the side of said photosensitive layer is covered by the opaque layer.

8. The electron beam recording material as set forth in claim 1, wherein the sides of said photosensitive layer and the support are covered by the opaque layer. 

2. The electron beam recording material as set forth in claim 1, wherein said support is a plastic base.
 3. The electron beam recording material as set forth in claim 1, wherein said opaque layer formed on the silver halide photosensitive layer is a mixture of a polymer and one material of the group consisting of a pigment and a dye.
 4. The electron beam recording material as set forth in claim 1, wherein said opaque layer formed on the back side of the support is a mixture of a polymer and one material of the group consisting of a pigment and a dye.
 5. The electron beam recording material as set forth in claim 1, wherein the thickness of the opaque layer on the photosensitive layer is 0.2-5 microns and the thickness of the opaque layer on the back side of the suppoRt is 1-10 microns.
 6. The electron beam recording material as set forth in claim 1, wherein at least one of said opaque layers is made of pitch.
 7. The electron beam recording material as set forth in claim 1, wherein the side of said photosensitive layer is covered by the opaque layer.
 8. The electron beam recording material as set forth in claim 1, wherein the sides of said photosensitive layer and the support are covered by the opaque layer. 